Dynamic player selection for audio signal processing

ABSTRACT

In one aspect, a first playback device is configured to (i) receive a set of voice signals, (ii) process the set of voice signals using a first set of audio processing algorithms, (iii) identify, from the set of voice signals, at least two voice signals that are to be further processed, (iv) determine that the first playback device does not have a threshold amount of computational power available, (v) receive an indication of an available amount of computational power of a second playback device, (vi) send the at least two voice signals to the second playback device, (vii) cause the second playback device to process the at least two voice signals using a second set of audio processing algorithms, (viii) receive, from the second playback device, the processed at least two voice signals, and (ix) combine the processed at least two voice signals into a combined voice signal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to, and is a continuation of, U.S.Non-Provisional patent application Ser. No. 16/444,975, filed on Jun.18, 2019, and titled “Dynamic Player Selection for Audio SignalProcessing,” which is a continuation of U.S. Non-Provisional patentapplication Ser. No. 15/959,907, filed on Apr. 23, 2018, and titled“Dynamic Player Selection for Audio Signal Processing,” which is acontinuation of U.S. Non-Provisional patent application Ser. No.15/178,180, filed on Jun. 9, 2016, and titled “Dynamic Player Selectionfor Audio Signal Processing”, the contents of each of which isincorporated herein in its entirety.

FIELD OF THE DISCLOSURE

The disclosure is related to consumer goods and, more particularly, tomethods, systems, products, features, services, and other elementsdirected to media playback or some aspect thereof.

BACKGROUND

Options for accessing and listening to digital audio in an out-loudsetting were limited until in 2003, when SONOS, Inc. filed for one ofits first patent applications, entitled “Method for Synchronizing AudioPlayback between Multiple Networked Devices,” and began offering a mediaplayback system for sale in 2005. The Sonos Wireless HiFi System enablespeople to experience music from many sources via one or more networkedplayback devices. Through a software control application installed on asmartphone, tablet, or computer, one can play audio in any room that hasa networked playback device. Additionally, using the control device, forexample, different songs can be streamed to each room with a playbackdevice, rooms can be grouped together for synchronous playback, or thesame song can be heard in all rooms synchronously.

Given the ever growing interest in digital media, there continues to bea need to develop consumer-accessible technologies to further enhancethe listening experience.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, aspects, and advantages of the presently disclosed technologymay be better understood with regard to the following description,appended claims, and accompanying drawings where:

FIG. 1 shows an example playback system configuration in which certainembodiments may be practiced;

FIG. 2 shows a functional block diagram of an example playback device;

FIG. 3 shows a functional block diagram of an example control device;

FIG. 4 shows an example control device interface;

FIG. 5 shows an example network configuration in which certainembodiments may be practiced;

FIG. 6 shows a functional block diagram of an example network microphonedevice;

FIG. 7 shows an example environment in which certain embodiments may bepracticed;

FIG. 8 shows an example flow diagram associated with distributingprocessing across devices in a media playback system;

FIG. 9 shows a more detailed example flow diagram associated withdistributing processing across devices in the media playback system; and

FIG. 10 shows example tables for managing signal measures of audiosignals and spare computational power of devices in the media playbacksystem.

The drawings are for the purpose of illustrating example embodiments,but it is understood that the embodiments are not limited to thearrangements and instrumentality shown in the drawings.

DETAILED DESCRIPTION I. Overview

A media playback system may include one or more playback devices,network microphone devices, controller devices, and/or computingdevices. The playback device, network microphone device, controllerdevice, and computing device may collectively coordinate play back ofaudio content such as music tracks.

The playback device, the controller device, and the network microphonedevice may be in an environment such as a living room in a home. Amicrophone array of one or more of these devices may receive an audiosignal. The audio signal may include a sonic input and noise. The sonicinput may be a voice input such as a request to perform an actionassociated with the media playback system, e.g., “play audio” or “stopplaying audio”. The sonic input may take the form of any other voiceinput as well. The noise may be any type of audio other than the sonicinput. For example, the noise could include white noise or impulsenoise. Alternatively, the “noise” could be audio content played by aplayback device in the media playback system such as music.

It may be desirable to recover the sonic input from the audio signal.Embodiments described herein are directed to distributing, acrossdevices in the media playback system, processing associated withimproving a signal measure (e.g., signal to noise ratio) of the audiosignal received by a device in the media playback system prior to therecovery of the sonic input. The processing is distributed to reducedegradation in performance of a particular device in the media playbacksystem while the signal to noise ratio is improved. Improving the signalto noise ratio results in attenuating noise in the audio signal. Theimproved audio signal may then be passed to the computing device such asa server which is arranged to recover the sonic input. If the sonicinput is a voice input, the server may interpret the voice input todetermine the action associated with the voice input such as “play musicon a playback device” or to “turn off the playback device”. The servermay then cause the media playback system to perform the action.

As one example, an echo cancellation method may be used to improve thesignal to noise ratio of the audio signal received by a device in themedia playback system. The echo cancellation method seeks to removeechoes in the received audio signal. As another example, a beamformingmethod may be used to improve the signal to noise ratio of the audiosignal received by a device in the media playback system. Thebeamforming method may determine characteristics of an audio signalreceived in certain direction such as whether the sonic input of theaudio signal originates from the certain direction. In another example,one or more playback devices in the media playback system may be playingaudio content in the background as the sonic input is received. Themedia playback system may have knowledge of this audio content, e.g.,the spectral content of the audio content. The knowledge of the audioplaying in the background may be used to improve the signal to noiseratio of the audio signal.

The methods described above are examples of various methods of improvingthe signal to noise ratio which can be applied separately or together tothe audio signal to improve the signal to noise ratio. In this regard, adevice may apply one or more of the algorithms described above, i.e., afirst set of audio processing algorithms, to improve the signal to noiseratio of an audio signal that is received by the device. In embodiments,one or more of the received audio signal and the improved audio signalmay also be stored on the playback device, controller device, orcomputing device as audio files.

In addition to improving the signal to noise ratio of the audio signal,a signal measure, such as the signal to noise ratio, for the audiosignal as improved by one of the example algorithms described above maybe calculated. The signal to noise ratio may be a ratio of the improvedaudio signal to the received audio signal. For example, the receivedaudio signal and the improved audio signal may be represented as impulseresponses. The impulse response of the improved audio signal may bedivided by the received audio signal to calculate the signal to noiseratio.

A signal to noise ratio may be associated with each microphone array.For example, the echo cancellation algorithm provides an improved audiosignal based on the audio signal received by the microphone array. Thesignal to noise ratio is based on this improved audio signal. Further,this signal to noise ratio may be also be associated with the device ofthe microphone array.

Alternatively, a plurality of signal to noise ratios may be associatedwith the microphone array. Each direction of a plurality of directionsprocessed by a beamforming algorithm may have an associated signal tonoise ratio. For example, the audio signal may be processed atdirections of 20 degree angular intervals around the microphone array.Each 20 degree angular interval (18 intervals in total over 360 degrees)may have an associated impulse response of the received audio signal,impulse response of the improved audio signal, and signal to noiseratio.

The signal to noise ratios may be stored in a table. The table may alsostore an indication of the device/microphone array associated with asignal to noise ratio. In the case of beamforming, the table may alsostore an indication of a direction associated with the signal to noiseratio. The table may also be sorted such that the first entry in thetable may identify the highest signal to noise ratio for the audiosignal and the last entry may identify the lowest signal to noise ratiofor the audio signal.

The respective processors of devices in the media playback system mayhave spare computational power. The spare computational power may bethat computational power beyond what may be necessary to perform certainfunctions of the device. For example, the playback device may usecomputational power to play back audio but all the computational powermay not be needed to play back the audio. The remaining computationalpower may be considered spare and could be used for further processingof the audio signal such as improving the signal to noise ratio of theaudio signal received by a device.

Each device may indicate its spare computational power to a givendevice, such as a playback device, controller device, or server in themedia playback system. For example, the spare computational power may beindicated by a state variable of the media playback system. This statevariable may be periodically updated and made available to the devicesin the media playback system. In some examples, the state variable maytake the form of a flag which indicates that that playback device has aspare computational power. Further, various types of flags may be setdepending on an amount of spare computational power available. Based onthe state variable, the given device in the media playback system mayobtain the spare computational power for each device and generate atable that identifies for each device its spare processing power. Thespare computational power of each device in the media playback devicemay be organized in a table. Further, the table may be ordered based onavailability of processing power. For example, the first entry in thetable may be the device with a highest spare processing power and thelast entry may identify the device with a lowest spare processing power.Other arrangements are also possible.

Then, processing tasks are assigned to the devices based on its sparecomputational power as defined by the table and computational powerrequired by a processing task. The processing tasks may be defined by asecond set of audio processing algorithms which includes the echocancellation method, beamforming method, and/or subtraction of knownsignal method, among other. Each of these methods may have a higherresolution as compared to the first set of audio processing algorithms.The higher resolution processing may result in a further improvement ofthe signal to noise ratio of the audio signal as compared the first setof audio processing algorithms applied by the device when the audiosignal was received.

The given device may assign impulse responses of one or more of theaudio signals received by the device based on the spare computationalpower of a device and signal to noise ratios of the impulse responses.The impulse responses processed by each device based on the second setof audio processing algorithms result in an improved audio signal with ahigher signal to noise ratio than what was previously determined withthe first set of audio processing algorithms. Further, by usingavailable spare computational power, performance of the media playbackdevice is not degraded as a result of the additional processing.

The improved audio signal may also be weighted. The weighing may bebased on a confidence level. The improved audio signals may then becombined. The combined signal may result in cancellation of any noise inthe improved audio signal processed by the second set of audioprocessing algorithms. This combined audio signal may be then passed toa computing device such as a server for further processing.

Moving on from the above illustration, in one example embodiment, anetwork device may comprise a network interface; a processor comprisinginstructions, which when executed, cause the processor to: receive a setof signal measures, wherein each signal measure in the set of signalmeasures corresponds to a respective audio signal received by a devicein a media playback system which is processed based on a first set ofaudio processing algorithms; identify a plurality of signal measures inthe set of signal measures; cause, via the network interface, audiosignals corresponding to the identified plurality of signal measures tobe processed by one or more devices in the media playback system so asto improve a signal measure of each of the audio signals, wherein theaudio signals are processed based on a second set of audio processingalgorithms; and combine the processed audio signals into a combinedaudio signal. An algorithm of the second set of audio processingalgorithms may process the audio signals based on content played by aplayback device of the media playback system. Causing the audio signalscorresponding to the identified plurality of signal measures to beprocessed by one or more devices in the media playback system maycomprise receiving an indication of spare computational power from theone or more devices, identifying which devices have a sparecomputational power above a threshold amount, and causing the audiosignals corresponding to the identified plurality of signal measures tobe processed by the identified devices. A resolution of the first set ofaudio processing algorithms may be lower than a resolution of the secondset of audio processing algorithms. The network device may furthercomprise instructions for causing the processor to send, via the networkconnection, the combined audio signal to a server. The first set ofaudio processing algorithms and the second set of audio processingalgorithms may comprise one or more of an echo cancellation algorithmand a beamforming algorithm. Combining the processed audio signals intoa combined audio signal may comprise weighting one or more of theprocessed audio signals. The audio signals may be impulse responses. Asignal measure of the combined processed audio signals may be higherthan any of the audio signals with improved signal measures. Theidentified plurality of signal measures in the set of signal measuresmay be those with signal to noise ratios above a threshold amount.

In another example embodiment, a method may comprise: receiving a set ofsignal measures, wherein each signal measure in the set of signalmeasures corresponds to a respective audio signal received by a devicein a media playback system which is processed based on a first set ofaudio processing algorithms; identifying a plurality of signal measuresin the set of signal measures; causing audio signals corresponding tothe identified plurality of signal measures to be processed by one ormore devices in the media playback system to improve a signal measure ofeach of the audio signals, wherein the audio signals are processed basedon a second set of audio processing algorithms; and combining theprocessed audio signals into a combined audio signal. Causing the audiosignals corresponding to the identified plurality of signal measures tobe processed by one or more devices in the media playback system maycomprise receiving an indication of spare computational power from eachdevice in the media playback system, identifying which devices have aspare computational power above a threshold amount, and causing theaudio signals corresponding to the identified plurality of signalmeasures to be processed by the identified devices. Combining the audiosignals with improved signal measures into a combined audio signal maycomprise weighting one or more of the processed audio signals. Themethod may further comprise sending the combined audio signal to aserver. The first set of audio processing algorithms and the second setof audio processing algorithms may comprise one or more of an echocancellation algorithm and a beamforming algorithm. The identifiedplurality of signal measures in the set of signal measures may be thosewith signal to noise ratios above a threshold amount.

In yet another example embodiment, a computer readable storage mediummay include instructions for execution by a processor, the instructions,when executed, cause the processor to implement a method comprising:receiving a set of signal measures, wherein each signal measure in theset of signal measures corresponds to a respective audio signal receivedby a device in a media playback system which is processed based on afirst set of audio processing algorithms; identifying a plurality ofsignal measures in the set of signal measures; causing audio signalscorresponding to the identified plurality of signal measures to beprocessed by one or more devices in the media playback system to improvea signal measure of each of the audio signals, wherein the audio signalsare processed based on a second set of audio processing algorithms; andcombining the processed audio signals into a combined audio signal.Causing the audio signals corresponding to the identified plurality ofsignal measures to be processed by one or more devices in the mediaplayback system may comprise receiving an indication of sparecomputational power from the one or more devices, identifying whichdevices have a spare computational power above a threshold amount, andcausing the audio signals corresponding to the identified plurality ofsignal measures to be processed by the identified devices. Combining theprocessed audio signals into a combined audio signal may compriseweighting one or more of the processed audio signals.

II. Example Operating Environment

FIG. 1 shows an example configuration of a media playback system 100 inwhich one or more embodiments disclosed herein may be practiced orimplemented. The media playback system 100 as shown is associated withan example home environment having several rooms and spaces, such as forexample, a master bedroom, an office, a dining room, and a living room.As shown in the example of FIG. 1, the media playback system 100includes playback devices 102-124, control devices 126 and 128, and awired or wireless network router 130.

Further discussions relating to the different components of the examplemedia playback system 100 and how the different components may interactto provide a user with a media experience may be found in the followingsections. While discussions herein may generally refer to the examplemedia playback system 100, technologies described herein are not limitedto applications within, among other things, the home environment asshown in FIG. 1. For instance, the technologies described herein may beuseful in environments where multi-zone audio may be desired, such as,for example, a commercial setting like a restaurant, mall or airport, avehicle like a sports utility vehicle (SUV), bus or car, a ship or boat,an airplane, and so on.

a. Example Playback Devices

FIG. 2 shows a functional block diagram of an example playback device200 that may be configured to be one or more of the playback devices102-124 of the media playback system 100 of FIG. 1. The playback device200 may include a processor 202, software components 204, memory 206,audio processing components 208, audio amplifier(s) 210, speaker(s) 212,a network interface 214 including wireless interface(s) 216 and wiredinterface(s) 218, and microphone(s) 220. In one case, the playbackdevice 200 may not include the speaker(s) 212, but rather a speakerinterface for connecting the playback device 200 to external speakers.In another case, the playback device 200 may include neither thespeaker(s) 212 nor the audio amplifier(s) 210, but rather an audiointerface for connecting the playback device 200 to an external audioamplifier or audio-visual receiver.

In one example, the processor 202 may be a clock-driven computingcomponent configured to process input data according to instructionsstored in the memory 206. The memory 206 may be a tangiblecomputer-readable medium configured to store instructions executable bythe processor 202. For instance, the memory 206 may be data storage thatcan be loaded with one or more of the software components 204 executableby the processor 202 to achieve certain functions. In one example, thefunctions may involve the playback device 200 retrieving audio data froman audio source or another playback device. In another example, thefunctions may involve the playback device 200 sending audio data toanother device or playback device on a network. In yet another example,the functions may involve pairing of the playback device 200 with one ormore playback devices to create a multi-channel audio environment.

Certain functions may involve the playback device 200 synchronizingplayback of audio content with one or more other playback devices.During synchronous playback, a listener will preferably not be able toperceive time-delay differences between playback of the audio content bythe playback device 200 and the one or more other playback devices. U.S.Pat. No. 8,234,395 entitled, “System and method for synchronizingoperations among a plurality of independently clocked digital dataprocessing devices,” which is hereby incorporated by reference, providesin more detail some examples for audio playback synchronization amongplayback devices.

The memory 206 may further be configured to store data associated withthe playback device 200, such as one or more zones and/or zone groupsthe playback device 200 is a part of, audio sources accessible by theplayback device 200, or a playback queue that the playback device 200(or some other playback device) may be associated with. The data may bestored as one or more state variables that are periodically updated andused to describe the state of the playback device 200. The memory 206may also include the data associated with the state of the other devicesof the media system, and shared from time to time among the devices sothat one or more of the devices have the most recent data associatedwith the system. Other embodiments are also possible.

The audio processing components 208 may include one or moredigital-to-analog converters (DAC), an audio preprocessing component, anaudio enhancement component or a digital signal processor (DSP), and soon. In one embodiment, one or more of the audio processing components208 may be a subcomponent of the processor 202. In one example, audiocontent may be processed and/or intentionally altered by the audioprocessing components 208 to produce audio signals. The produced audiosignals may then be provided to the audio amplifier(s) 210 foramplification and playback through speaker(s) 212. Particularly, theaudio amplifier(s) 210 may include devices configured to amplify audiosignals to a level for driving one or more of the speakers 212. Thespeaker(s) 212 may include an individual transducer (e.g., a “driver”)or a complete speaker system involving an enclosure with one or moredrivers. A particular driver of the speaker(s) 212 may include, forexample, a subwoofer (e.g., for low frequencies), a mid-range driver(e.g., for middle frequencies), and/or a tweeter (e.g., for highfrequencies). In some cases, each transducer in the one or more speakers212 may be driven by an individual corresponding audio amplifier of theaudio amplifier(s) 210. In addition to producing analog signals forplayback by the playback device 200, the audio processing components 208may be configured to process audio content to be sent to one or moreother playback devices for playback.

Audio content to be processed and/or played back by the playback device200 may be received from an external source, such as via an audioline-in input connection (e.g., an auto-detecting 3.5 mm audio line-inconnection) or the network interface 214.

The network interface 214 may be configured to facilitate a data flowbetween the playback device 200 and one or more other devices on a datanetwork. As such, the playback device 200 may be configured to receiveaudio content over the data network from one or more other playbackdevices in communication with the playback device 200, network deviceswithin a local area network, or audio content sources over a wide areanetwork such as the Internet. In one example, the audio content andother signals transmitted and received by the playback device 200 may betransmitted in the form of digital packet data containing an InternetProtocol (IP)-based source address and IP-based destination addresses.In such a case, the network interface 214 may be configured to parse thedigital packet data such that the data destined for the playback device200 is properly received and processed by the playback device 200.

As shown, the network interface 214 may include wireless interface(s)216 and wired interface(s) 218. The wireless interface(s) 216 mayprovide network interface functions for the playback device 200 towirelessly communicate with other devices (e.g., other playbackdevice(s), speaker(s), receiver(s), network device(s), control device(s)within a data network the playback device 200 is associated with) inaccordance with a communication protocol (e.g., any wireless standardincluding IEEE 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, 802.15, 4Gmobile communication standard, and so on). The wired interface(s) 218may provide network interface functions for the playback device 200 tocommunicate over a wired connection with other devices in accordancewith a communication protocol (e.g., IEEE 802.3). While the networkinterface 214 shown in FIG. 2 includes both wireless interface(s) 216and wired interface(s) 218, the network interface 214 may in someembodiments include only wireless interface(s) or only wiredinterface(s).

The microphone(s) 220 may be arranged to detect sound in the environmentof the playback device 200. For instance, the microphone(s) may bemounted on an exterior wall of a housing of the playback device. Themicrophone(s) may be any type of microphone now known or later developedsuch as a condenser microphone, electret condenser microphone, or adynamic microphone. The microphone(s) may be sensitive to a portion ofthe frequency range of the speaker(s) 220. One or more of the speaker(s)220 may operate in reverse as the microphone(s) 220. In some aspects,the playback device 200 might not have microphone(s) 220.

In one example, the playback device 200 and one other playback devicemay be paired to play two separate audio components of audio content.For instance, playback device 200 may be configured to play a leftchannel audio component, while the other playback device may beconfigured to play a right channel audio component, thereby producing orenhancing a stereo effect of the audio content. The paired playbackdevices (also referred to as “bonded playback devices”) may further playaudio content in synchrony with other playback devices.

In another example, the playback device 200 may be sonicallyconsolidated with one or more other playback devices to form a single,consolidated playback device. A consolidated playback device may beconfigured to process and reproduce sound differently than anunconsolidated playback device or playback devices that are paired,because a consolidated playback device may have additional speakerdrivers through which audio content may be rendered. For instance, ifthe playback device 200 is a playback device designed to render lowfrequency range audio content (i.e. a subwoofer), the playback device200 may be consolidated with a playback device designed to render fullfrequency range audio content. In such a case, the full frequency rangeplayback device, when consolidated with the low frequency playbackdevice 200, may be configured to render only the mid and high frequencycomponents of audio content, while the low frequency range playbackdevice 200 renders the low frequency component of the audio content. Theconsolidated playback device may further be paired with a singleplayback device or yet another consolidated playback device.

By way of illustration, SONOS, Inc. presently offers (or has offered)for sale certain playback devices including a “PLAY:1,” “PLAY:3,”“PLAY:5,” “PLAYBAR,” “CONNECT:AMP,” “CONNECT,” and “SUB.” Any otherpast, present, and/or future playback devices may additionally oralternatively be used to implement the playback devices of exampleembodiments disclosed herein. Additionally, it is understood that aplayback device is not limited to the example illustrated in FIG. 2 orto the SONOS product offerings. For example, a playback device mayinclude a wired or wireless headphone. In another example, a playbackdevice may include or interact with a docking station for personalmobile media playback devices. In yet another example, a playback devicemay be integral to another device or component such as a television, alighting fixture, or some other device for indoor or outdoor use.

b. Example Playback Zone Configurations

Referring back to the media playback system 100 of FIG. 1, theenvironment may have one or more playback zones, each with one or moreplayback devices. The media playback system 100 may be established withone or more playback zones, after which one or more zones may be added,or removed to arrive at the example configuration shown in FIG. 1. Eachzone may be given a name according to a different room or space such asan office, bathroom, master bedroom, bedroom, kitchen, dining room,living room, and/or balcony. In one case, a single playback zone mayinclude multiple rooms or spaces. In another case, a single room orspace may include multiple playback zones.

As shown in FIG. 1, the balcony, dining room, kitchen, bathroom, office,and bedroom zones each have one playback device, while the living roomand master bedroom zones each have multiple playback devices. In theliving room zone, playback devices 104, 106, 108, and 110 may beconfigured to play audio content in synchrony as individual playbackdevices, as one or more bonded playback devices, as one or moreconsolidated playback devices, or any combination thereof. Similarly, inthe case of the master bedroom, playback devices 122 and 124 may beconfigured to play audio content in synchrony as individual playbackdevices, as a bonded playback device, or as a consolidated playbackdevice.

In one example, one or more playback zones in the environment of FIG. 1may each be playing different audio content. For instance, the user maybe grilling in the balcony zone and listening to hip hop music beingplayed by the playback device 102 while another user may be preparingfood in the kitchen zone and listening to classical music being playedby the playback device 114. In another example, a playback zone may playthe same audio content in synchrony with another playback zone. Forinstance, the user may be in the office zone where the playback device118 is playing the same rock music that is being playing by playbackdevice 102 in the balcony zone. In such a case, playback devices 102 and118 may be playing the rock music in synchrony such that the user mayseamlessly (or at least substantially seamlessly) enjoy the audiocontent that is being played out-loud while moving between differentplayback zones. Synchronization among playback zones may be achieved ina manner similar to that of synchronization among playback devices, asdescribed in previously referenced U.S. Pat. No. 8,234,395.

As suggested above, the zone configurations of the media playback system100 may be dynamically modified, and in some embodiments, the mediaplayback system 100 supports numerous configurations. For instance, if auser physically moves one or more playback devices to or from a zone,the media playback system 100 may be reconfigured to accommodate thechange(s). For instance, if the user physically moves the playbackdevice 102 from the balcony zone to the office zone, the office zone maynow include both the playback device 118 and the playback device 102.The playback device 102 may be paired or grouped with the office zoneand/or renamed if so desired via a control device such as the controldevices 126 and 128. On the other hand, if the one or more playbackdevices are moved to a particular area in the home environment that isnot already a playback zone, a new playback zone may be created for theparticular area.

Further, different playback zones of the media playback system 100 maybe dynamically combined into zone groups or split up into individualplayback zones. For instance, the dining room zone and the kitchen zone114 may be combined into a zone group for a dinner party such thatplayback devices 112 and 114 may render audio content in synchrony. Onthe other hand, the living room zone may be split into a television zoneincluding playback device 104, and a listening zone including playbackdevices 106, 108, and 110, if the user wishes to listen to music in theliving room space while another user wishes to watch television.

c. Example Control Devices

FIG. 3 shows a functional block diagram of an example control device 300that may be configured to be one or both of the control devices 126 and128 of the media playback system 100. As shown, the control device 300may include a processor 302, memory 304, a network interface 306, a userinterface 308, microphone(s) 310, and software components 312. In oneexample, the control device 300 may be a dedicated controller for themedia playback system 100. In another example, the control device 300may be a network device on which media playback system controllerapplication software may be installed, such as for example, an iPhone™,iPad™ or any other smart phone, tablet or network device (e.g., anetworked computer such as a PC or Mac™).

The processor 302 may be configured to perform functions relevant tofacilitating user access, control, and configuration of the mediaplayback system 100. The memory 304 may be data storage that can beloaded with one or more of the software components executable by theprocessor 302 to perform those functions. The memory 304 may also beconfigured to store the media playback system controller applicationsoftware and other data associated with the media playback system 100and the user.

In one example, the network interface 306 may be based on an industrystandard (e.g., infrared, radio, wired standards including IEEE 802.3,wireless standards including IEEE 802.11a, 802.11b, 802.11g, 802.11n,802.11ac, 802.15, 4G mobile communication standard, and so on). Thenetwork interface 306 may provide a means for the control device 300 tocommunicate with other devices in the media playback system 100. In oneexample, data and information (e.g., such as a state variable) may becommunicated between control device 300 and other devices via thenetwork interface 306. For instance, playback zone and zone groupconfigurations in the media playback system 100 may be received by thecontrol device 300 from a playback device or another network device, ortransmitted by the control device 300 to another playback device ornetwork device via the network interface 306. In some cases, the othernetwork device may be another control device.

Playback device control commands such as volume control and audioplayback control may also be communicated from the control device 300 toa playback device via the network interface 306. As suggested above,changes to configurations of the media playback system 100 may also beperformed by a user using the control device 300. The configurationchanges may include adding/removing one or more playback devices to/froma zone, adding/removing one or more zones to/from a zone group, forminga bonded or consolidated player, separating one or more playback devicesfrom a bonded or consolidated player, among others. Accordingly, thecontrol device 300 may sometimes be referred to as a controller, whetherthe control device 300 is a dedicated controller or a network device onwhich media playback system controller application software isinstalled.

Control device 300 may include microphone(s) 310. Microphone(s) 310 maybe arranged to detect sound in the environment of the control device300. Microphone(s) 310 may be any type of microphone now known or laterdeveloped such as a condenser microphone, electret condenser microphone,or a dynamic microphone. The microphone(s) may be sensitive to a portionof a frequency range. Two or more microphones 310 may be arranged tocapture location information of an audio source (e.g., voice, audiblesound) and/or to assist in filtering background noise.

The user interface 308 of the control device 300 may be configured tofacilitate user access and control of the media playback system 100, byproviding a controller interface such as the controller interface 400shown in FIG. 4. The controller interface 400 includes a playbackcontrol region 410, a playback zone region 420, a playback status region430, a playback queue region 440, and an audio content sources region450. The user interface 400 as shown is just one example of a userinterface that may be provided on a network device such as the controldevice 300 of FIG. 3 (and/or the control devices 126 and 128 of FIG. 1)and accessed by users to control a media playback system such as themedia playback system 100. Other user interfaces of varying formats,styles, and interactive sequences may alternatively be implemented onone or more network devices to provide comparable control access to amedia playback system.

The playback control region 410 may include selectable (e.g., by way oftouch or by using a cursor) icons to cause playback devices in aselected playback zone or zone group to play or pause, fast forward,rewind, skip to next, skip to previous, enter/exit shuffle mode,enter/exit repeat mode, enter/exit cross fade mode. The playback controlregion 410 may also include selectable icons to modify equalizationsettings, and playback volume, among other possibilities.

The playback zone region 420 may include representations of playbackzones within the media playback system 100. In some embodiments, thegraphical representations of playback zones may be selectable to bringup additional selectable icons to manage or configure the playback zonesin the media playback system, such as a creation of bonded zones,creation of zone groups, separation of zone groups, and renaming of zonegroups, among other possibilities.

For example, as shown, a “group” icon may be provided within each of thegraphical representations of playback zones. The “group” icon providedwithin a graphical representation of a particular zone may be selectableto bring up options to select one or more other zones in the mediaplayback system to be grouped with the particular zone. Once grouped,playback devices in the zones that have been grouped with the particularzone will be configured to play audio content in synchrony with theplayback device(s) in the particular zone. Analogously, a “group” iconmay be provided within a graphical representation of a zone group. Inthis case, the “group” icon may be selectable to bring up options todeselect one or more zones in the zone group to be removed from the zonegroup. Other interactions and implementations for grouping andungrouping zones via a user interface such as the user interface 400 arealso possible. The representations of playback zones in the playbackzone region 420 may be dynamically updated as playback zone or zonegroup configurations are modified.

The playback status region 430 may include graphical representations ofaudio content that is presently being played, previously played, orscheduled to play next in the selected playback zone or zone group. Theselected playback zone or zone group may be visually distinguished onthe user interface, such as within the playback zone region 420 and/orthe playback status region 430. The graphical representations mayinclude track title, artist name, album name, album year, track length,and other relevant information that may be useful for the user to knowwhen controlling the media playback system via the user interface 400.

The playback queue region 440 may include graphical representations ofaudio content in a playback queue associated with the selected playbackzone or zone group. In some embodiments, each playback zone or zonegroup may be associated with a playback queue containing informationcorresponding to zero or more audio items for playback by the playbackzone or zone group. For instance, each audio item in the playback queuemay comprise a uniform resource identifier (URI), a uniform resourcelocator (URL) or some other identifier that may be used by a playbackdevice in the playback zone or zone group to find and/or retrieve theaudio item from a local audio content source or a networked audiocontent source, possibly for playback by the playback device.

In one example, a playlist may be added to a playback queue, in whichcase information corresponding to each audio item in the playlist may beadded to the playback queue. In another example, audio items in aplayback queue may be saved as a playlist. In a further example, aplayback queue may be empty, or populated but “not in use” when theplayback zone or zone group is playing continuously streaming audiocontent, such as Internet radio that may continue to play untilotherwise stopped, rather than discrete audio items that have playbackdurations. In an alternative embodiment, a playback queue can includeInternet radio and/or other streaming audio content items and be “inuse” when the playback zone or zone group is playing those items. Otherexamples are also possible.

When playback zones or zone groups are “grouped” or “ungrouped,”playback queues associated with the affected playback zones or zonegroups may be cleared or re-associated. For example, if a first playbackzone including a first playback queue is grouped with a second playbackzone including a second playback queue, the established zone group mayhave an associated playback queue that is initially empty, that containsaudio items from the first playback queue (such as if the secondplayback zone was added to the first playback zone), that contains audioitems from the second playback queue (such as if the first playback zonewas added to the second playback zone), or a combination of audio itemsfrom both the first and second playback queues. Subsequently, if theestablished zone group is ungrouped, the resulting first playback zonemay be re-associated with the previous first playback queue, or beassociated with a new playback queue that is empty or contains audioitems from the playback queue associated with the established zone groupbefore the established zone group was ungrouped. Similarly, theresulting second playback zone may be re-associated with the previoussecond playback queue, or be associated with a new playback queue thatis empty, or contains audio items from the playback queue associatedwith the established zone group before the established zone group wasungrouped. Other examples are also possible.

Referring back to the user interface 400 of FIG. 4, the graphicalrepresentations of audio content in the playback queue region 440 mayinclude track titles, artist names, track lengths, and other relevantinformation associated with the audio content in the playback queue. Inone example, graphical representations of audio content may beselectable to bring up additional selectable icons to manage and/ormanipulate the playback queue and/or audio content represented in theplayback queue. For instance, a represented audio content may be removedfrom the playback queue, moved to a different position within theplayback queue, or selected to be played immediately, or after anycurrently playing audio content, among other possibilities. A playbackqueue associated with a playback zone or zone group may be stored in amemory on one or more playback devices in the playback zone or zonegroup, on a playback device that is not in the playback zone or zonegroup, and/or some other designated device.

The audio content sources region 450 may include graphicalrepresentations of selectable audio content sources from which audiocontent may be retrieved and played by the selected playback zone orzone group. Discussions pertaining to audio content sources may be foundin the following section.

d. Example Audio Content Sources

As indicated previously, one or more playback devices in a zone or zonegroup may be configured to retrieve for playback audio content (e.g.according to a corresponding URI or URL for the audio content) from avariety of available audio content sources. In one example, audiocontent may be retrieved by a playback device directly from acorresponding audio content source (e.g., a line-in connection). Inanother example, audio content may be provided to a playback device overa network via one or more other playback devices or network devices.

Example audio content sources may include a memory of one or moreplayback devices in a media playback system such as the media playbacksystem 100 of FIG. 1, local music libraries on one or more networkdevices (such as a control device, a network-enabled personal computer,or a networked-attached storage (NAS), for example), streaming audioservices providing audio content via the Internet (e.g., the cloud), oraudio sources connected to the media playback system via a line-in inputconnection on a playback device or network devise, among otherpossibilities.

In some embodiments, audio content sources may be regularly added orremoved from a media playback system such as the media playback system100 of FIG. 1. In one example, an indexing of audio items may beperformed whenever one or more audio content sources are added, removedor updated. Indexing of audio items may involve scanning foridentifiable audio items in all folders/directory shared over a networkaccessible by playback devices in the media playback system, andgenerating or updating an audio content database containing metadata(e.g., title, artist, album, track length, among others) and otherassociated information, such as a URI or URL for each identifiable audioitem found. Other examples for managing and maintaining audio contentsources may also be possible.

The above discussions relating to playback devices, controller devices,playback zone configurations, and media content sources provide onlysome examples of operating environments within which functions andmethods described below may be implemented. Other operating environmentsand configurations of media playback systems, playback devices, andnetwork devices not explicitly described herein may also be applicableand suitable for implementation of the functions and methods.

e. Example Plurality of Networked Devices

FIG. 5 shows an example plurality of devices 500 that may be configuredto provide an audio playback experience based on voice control. Onehaving ordinary skill in the art will appreciate that the devices shownin FIG. 5 are for illustrative purposes only, and variations includingdifferent and/or additional devices may be possible. As shown, theplurality of devices 500 includes computing devices 504, 506, and 508;network microphone devices (NMDs) 512, 514, and 516; playback devices(PBDs) 532, 534, 536, and 538; and a controller device (CR) 522.

Each of the plurality of devices 500 may be network-capable devices thatcan establish communication with one or more other devices in theplurality of devices according to one or more network protocols, such asNFC, Bluetooth, Ethernet, and IEEE 802.11, among other examples, overone or more types of networks, such as wide area networks (WAN), localarea networks (LAN), and personal area networks (PAN), among otherpossibilities.

As shown, the computing devices 504, 506, and 508 may be part of a cloudnetwork 502. The cloud network 502 may include additional computingdevices. In one example, the computing devices 504, 506, and 508 may bedifferent servers. In another example, two or more of the computingdevices 504, 506, and 508 may be modules of a single server.Analogously, each of the computing device 504, 506, and 508 may includeone or more modules or servers. For ease of illustration purposesherein, each of the computing devices 504, 506, and 508 may beconfigured to perform particular functions within the cloud network 502.For instance, computing device 508 may be a source of audio content fora streaming music service.

As shown, the computing device 504 may be configured to interface withNMDs 512, 514, and 516 via communication path 542. NMDs 512, 514, and516 may be components of one or more “Smart Home” systems. In one case,NMDs 512, 514, and 516 may be physically distributed throughout ahousehold, similar to the distribution of devices shown in FIG. 1. Inanother case, two or more of the NMDs 512, 514, and 516 may bephysically positioned within relative close proximity of one another.Communication path 542 may comprise one or more types of networks, suchas a WAN including the Internet, LAN, and/or PAN, among otherpossibilities.

In one example, one or more of the NMDs 512, 514, and 516 may be devicesconfigured primarily for audio detection. In another example, one ormore of the NMDs 512, 514, and 516 may be components of devices havingvarious primary utilities. For instance, as discussed above inconnection to FIGS. 2 and 3, one or more of NMDs 512, 514, and 516 maybe the microphone(s) 220 of playback device 200 or the microphone(s) 310of network device 300. Further, in some cases, one or more of NMDs 512,514, and 516 may be the playback device 200 or network device 300. In anexample, one or more of NMDs 512, 514, and/or 516 may include multiplemicrophones arranged in a microphone array.

As shown, the computing device 506 may be configured to interface withCR 522 and PBDs 532, 534, 536, and 538 via communication path 544. Inone example, CR 522 may be a network device such as the network device200 of FIG. 2. Accordingly, CR 522 may be configured to provide thecontroller interface 400 of FIG. 4. Similarly, PBDs 532, 534, 536, and538 may be playback devices such as the playback device 300 of FIG. 3.As such, PBDs 532, 534, 536, and 538 may be physically distributedthroughout a household as shown in FIG. 1. For illustration purposes,PBDs 536 and 538 may be part of a bonded zone 530, while PBDs 532 and534 may be part of their own respective zones. As described above, thePBDs 532, 534, 536, and 538 may be dynamically bonded, grouped,unbonded, and ungrouped. Communication path 544 may comprise one or moretypes of networks, such as a WAN including the Internet, LAN, and/orPAN, among other possibilities.

In one example, as with NMDs 512, 514, and 516, CR522 and PBDs 532, 534,536, and 538 may also be components of one or more “Smart Home” systems.In one case, PBDs 532, 534, 536, and 538 may be distributed throughoutthe same household as the NMDs 512, 514, and 516. Further, as suggestedabove, one or more of PBDs 532, 534, 536, and 538 may be one or more ofNMDs 512, 514, and 516.

The NMDs 512, 514, and 516 may be part of a local area network, and thecommunication path 542 may include an access point that links the localarea network of the NMDs 512, 514, and 516 to the computing device 504over a WAN (communication path not shown). Likewise, each of the NMDs512, 514, and 516 may communicate with each other via such an accesspoint.

Similarly, CR 522 and PBDs 532, 534, 536, and 538 may be part of a localarea network and/or a local playback network as discussed in previoussections, and the communication path 544 may include an access pointthat links the local area network and/or local playback network of CR522 and PBDs 532, 534, 536, and 538 to the computing device 506 over aWAN. As such, each of the CR 522 and PBDs 532, 534, 536, and 538 mayalso communicate with each over such an access point.

In one example, communication paths 542 and 544 may comprise the sameaccess point. In an example, each of the NMDs 512, 514, and 516, CR 522,and PBDs 532, 534, 536, and 538 may access the cloud network 502 via thesame access point for a household.

As shown in FIG. 5, each of the NMDs 512, 514, and 516, CR 522, and PBDs532, 534, 536, and 538 may also directly communicate with one or more ofthe other devices via communication means 546. Communication means 546as described herein may involve one or more forms of communicationbetween the devices, according to one or more network protocols, overone or more types of networks, and/or may involve communication via oneor more other network devices. For instance, communication means 546 mayinclude one or more of for example, Bluetooth™ (IEEE 802.15), NFC,Wireless direct, and/or Proprietary wireless, among other possibilities.

In one example, CR 522 may communicate with NMD 512 over Bluetooth™, andcommunicate with PBD 534 over another local area network. In anotherexample, NMD 514 may communicate with CR 522 over another local areanetwork, and communicate with PBD 536 over Bluetooth. In a furtherexample, each of the PBDs 532, 534, 536, and 538 may communicate witheach other according to a spanning tree protocol over a local playbacknetwork, while each communicating with CR 522 over a local area network,different from the local playback network. Other examples are alsopossible.

In some cases, communication means between the NMDs 512, 514, and 516,CR 522, and PBDs 532, 534, 536, and 538 may change depending on types ofcommunication between the devices, network conditions, and/or latencydemands. For instance, communication means 546 may be used when NMD 516is first introduced to the household with the PBDs 532, 534, 536, and538. In one case, the NMD 516 may transmit identification informationcorresponding to the NMD 516 to PBD 538 via NFC, and PBD 538 may inresponse, transmit local area network information to NMD 516 via NFC (orsome other form of communication). However, once NMD 516 has beenconfigured within the household, communication means between NMD 516 andPBD 538 may change. For instance, NMD 516 may subsequently communicatewith PBD 538 via communication path 542, the cloud network 502, andcommunication path 544. In another example, the NMDs and PBDs may nevercommunicate via local communications means 546. In a further example,the NMDs and PBDs may communicate primarily via local communicationsmeans 546. Other examples are also possible.

In an illustrative example, NMDs 512, 514, and 516 may be configured toreceive voice inputs to control PBDs 532, 534, 536, and 538. Theavailable control commands may include any media playback systemcontrols previously discussed, such as playback volume control, playbacktransport controls, music source selection, and grouping, among otherpossibilities. In one instance, NMD 512 may receive a voice input tocontrol one or more of the PBDs 532, 534, 536, and 538. In response toreceiving the voice input, NMD 512 may transmit via communication path542, the voice input to computing device 504 for processing. In oneexample, the computing device 504 may convert the voice input to anequivalent text command, and parse the text command to identify acommand. Computing device 504 may then subsequently transmit the textcommand to the computing device 506. In another example, the computingdevice 504 may convert the voice input to an equivalent text command,and then subsequently transmit the text command to the computing device506. The computing device 506 may then parse the text command toidentify one or more playback commands.

For instance, if the text command is “Play ‘Track 1’ by ‘Artist 1’ from‘Streaming Service 1’ in ‘Zone 1’,” The computing device 506 mayidentify (i) a URL for “Track 1” by “Artist 1” available from “StreamingService 1,” and (ii) at least one playback device in “Zone 1.” In thisexample, the URL for “Track 1” by “Artist 1” from “Streaming Service 1”may be a URL pointing to computing device 508, and “Zone 1” may be thebonded zone 530. As such, upon identifying the URL and one or both ofPBDs 536 and 538, the computing device 506 may transmit viacommunication path 544 to one or both of PBDs 536 and 538, theidentified URL for playback. One or both of PBDs 536 and 538 mayresponsively retrieve audio content from the computing device 508according to the received URL, and begin playing “Track 1” by “Artist 1”from “Streaming Service 1.”

One having ordinary skill in the art will appreciate that the above isjust one illustrative example, and that other implementations are alsopossible. In one case, operations performed by one or more of theplurality of devices 500, as described above, may be performed by one ormore other devices in the plurality of device 500. For instance, theconversion from voice input to the text command may be alternatively,partially, or wholly performed by another device or devices, such as NMD512, computing device 506, PBD 536, and/or PBD 538. Analogously, theidentification of the URL may be alternatively, partially, or whollyperformed by another device or devices, such as NMD 512, computingdevice 504, PBD 536, and/or PBD 538.

f. Example Network Microphone Device

FIG. 6 shows a function block diagram of an example network microphonedevice 600 that may be configured to be one or more of NMDs 512, 514,and 516 of FIG. 5. As shown, the network microphone device 600 includesa processor 602, memory 604, a microphone array 606, a network interface608, a user interface 610, software components 612, and speaker(s) 614.One having ordinary skill in the art will appreciate that other networkmicrophone device configurations and arrangements are also possible. Forinstance, network microphone devices may alternatively exclude thespeaker(s) 614 or have a single microphone instead of microphone array606.

The processor 602 may include one or more processors and/or controllers,which may take the form of a general or special-purpose processor orcontroller. For instance, the processing unit 602 may includemicroprocessors, microcontrollers, application-specific integratedcircuits, digital signal processors, and the like. The memory 604 may bedata storage that can be loaded with one or more of the softwarecomponents executable by the processor 602 to perform those functions.Accordingly, memory 604 may comprise one or more non-transitorycomputer-readable storage mediums, examples of which may includevolatile storage mediums such as random access memory, registers, cache,etc. and non-volatile storage mediums such as read-only memory, ahard-disk drive, a solid-state drive, flash memory, and/or anoptical-storage device, among other possibilities.

The microphone array 606 may be a plurality of microphones arranged todetect sound in the environment of the network microphone device 600.Microphone array 606 may include any type of microphone now known orlater developed such as a condenser microphone, electret condensermicrophone, or a dynamic microphone, among other possibilities. In oneexample, the microphone array may be arranged to detect audio from oneor more directions relative to the network microphone device. Themicrophone array 606 may be sensitive to a portion of a frequency range.In one example, a first subset of the microphone array 606 may besensitive to a first frequency range, while a second subset of themicrophone array may be sensitive to a second frequency range. Themicrophone array 606 may further be arranged to capture locationinformation of an audio source (e.g., voice, audible sound) and/or toassist in filtering background noise. Notably, in some embodiments themicrophone array may consist of only a single microphone, rather than aplurality of microphones.

The network interface 608 may be configured to facilitate wirelessand/or wired communication between various network devices, such as, inreference to FIG. 5, CR 522, PBDs 532-538, computing device 504-508 incloud network 502, and other network microphone devices, among otherpossibilities. As such, network interface 608 may take any suitable formfor carrying out these functions, examples of which may include anEthernet interface, a serial bus interface (e.g., FireWire, USB 2.0,etc.), a chipset and antenna adapted to facilitate wirelesscommunication, and/or any other interface that provides for wired and/orwireless communication. In one example, the network interface 608 may bebased on an industry standard (e.g., infrared, radio, wired standardsincluding IEEE 802.3, wireless standards including IEEE 802.11a,802.11b, 802.11g, 802.11n, 802.11ac, 802.15, 4G mobile communicationstandard, and so on).

The user interface 610 of the network microphone device 600 may beconfigured to facilitate user interactions with the network microphonedevice. In one example, the user interface 608 may include one or moreof physical buttons, graphical interfaces provided on touch sensitivescreen(s) and/or surface(s), among other possibilities, for a user todirectly provide input to the network microphone device 600. The userinterface 610 may further include one or more of lights and thespeaker(s) 614 to provide visual and/or audio feedback to a user. In oneexample, the network microphone device 600 may further be configured toplayback audio content via the speaker(s) 614.

III. Example Systems

The playback device, the controller device, and the network microphonedevice may be in an environment such as a living room in a home. Themicrophone array of one or more of these devices may receive an audiosignal. The audio signal may include an indication of a sonic input andnoise. The sonic input may be a voice input such as a request to performan action associated with the media playback system, e.g., “play audio”or “stop playing audio”. The sonic input may take the form of any othervoice input as well. The noise could include white noise or impulsenoise. Alternatively, the “noise” could be audio content played by aplayback device in the media playback system.

It may be desirable to recover the sonic input from the audio signalthat is received via the microphone array of a device. Examplesdescribed herein are directed to distributing, across devices in themedia playback system, processing associated with improving a signalmeasure (e.g., signal to noise ratio) of the audio signal received by adevice in the media playback system prior to the recovery of the sonicinput. The processing is distributed to reduce degradation inperformance of a particular device in the media playback system whilethe signal to noise ratio is improved. Improving the signal to noiseratio results in attenuating noise in the audio signal. The improvedaudio signal may then be passed to a computing device such as a serverwhich is arranged to recover the sonic input. If the sonic input is avoice input, the server may further interpret from voice input theaction associated with the voice input such as “play music on a playbackdevice” or to “turn off the playback device”. The server may then causethe media playback system to perform the action.

FIG. 7 illustrates an example environment 700 where audio signals may bepresent. The example environment may be a room of a home, such as aliving room or bedroom, which has a media playback system for playingaudio content. The media playback system may include one or moreplayback devices 702, network microphone devices 704, controller devices706, and/or computing devices (not shown). The playback device 702 mayhave one or more microphones (e.g., microphone arrays) for receiving anaudio signal, one or more speakers for playing back audio content, and aprocessor for playing back the audio content. The network microphonedevice 704 may have one or more microphones (e.g., microphone arrays)for receiving the audio signal and a processor for transmitting thereceived audio signal to the computing device. The controller device 706may have one or more microphones (e.g., microphone arrays) for receivingan audio signal and a processor for controlling the one or more playbackdevices in the media playback system. The computing device may be aserver which is arranged with a processor to perform various processingassociated with the media playback system. The processing may includeprocessing of the audio signal sent by the network microphone device704. The computing device may be located remote to devices in theenvironment 700 such as in a cloud network. The computing device mayalso source audio content to the one or more playback devices forplayback.

The example environment 700 may also have an audio source 710. The audiosource 710 may provide a sonic input. For example, the audio source 710may be a user of the media playback system who speaks in theenvironment. In this case, the audio source may be a voice input. Thesonic input produced by the audio source 710 may be directed in one ormore directions. In one example, the sonic input may be generallydirected toward a device in the media playback system. In anotherexample, sonic input may be directed away from the device in the mediaplayback system. In yet another example, the sonic input may be directeduniformly in all directions throughout the environment. In this regard,one or more of the microphone arrays of the playback device 702, NMD704, and/or controller device 706 may receive an audio signal thatincludes an indication of the sonic input.

The audio signal received by the microphone array may also receive anynoise present in the environment. The noise may be audio that isreceived by the device aside from the sonic input. For example, thenoise may include an attenuated version of the sonic input, and echoesof the sonic input, as a result of the sonic input traveling through theenvironment, bouncing off walls and objects in the environment beforereaching a microphone array. The “noise” could also be any audio contentbeing played back by a playback device such as music.

A signal to noise ratio is a signal measure indicative of a comparisonof a desired signal in the audio signal to the noise in the audiosignal. The desired signal may be the sonic input in the audio signaland the noise may be audio other than the sonic input in the audiosignal. The audio signal may have a relatively high signal to noiseratio if the device which receives the audio signal is in a samedirection as the sonic input. For example, the NMD 704 in the upper leftcorner of the environment 700 may receive an audio signal with a highsignal to noise ratio because the audio source 710 is outputting a sonicinput in the direction of the NMD 704. On the other hand, the audiosignal may have a relatively low signal to noise ratio if the devicewhich receives the audio signal is not in a same direction as the audiosource 710. For example, the NMD 704 in the lower right corner of theenvironment 700 may receive an audio signal with a low signal to noiseratio because the audio source 710 is not outputting a sonic input inthe direction of the NMD 704. The microphone array of the NMD 704 maystill receive the sonic input, but indirectly, for example, as a resultof the sonic input bouncing off walls of the environment, objects in theenvironment such as furniture, or the ceiling in the environment andreaching the microphone array.

In one example, the signal to noise ratio can be improved using echocancellation. The microphone array may receive multiple versions of theaudio signal having different phases and magnitudes depending on thepath that the audio signal took to reach the microphone array. Forexample, the audio signal may bounce off objects in an environment, suchas furniture, walls, and the ceiling, before being received by themicrophone array. The microphone array may receive multiple versions ofthe audio signal, i.e., echoes, and the multiple versions may arrive atthe microphone array at different times depending on how long the audiosignal takes to travel from the source to the microphone array.

Echo cancellation seeks to remove such “echoes” in the received audiosignal. The audio signal that is received by the microphone array may berepresented as a plurality of impulse responses. Each impulse responsemay be associated with a microphone of the microphone array. The impulseresponses may be time aligned based on a distance between microphonesassociated with a respective impulse response and combined into a singlesignal, e.g., a combined impulse response. Then, the combined impulseresponse may be divided into windows of time. For example, an impulseresponse of 1000 ms may be divided into overlapping and/ornon-overlapping windows of impulse responses of 100 ms for processing.The size of the windows of time may determine the improvement of thesignal to noise ratio, e.g., a larger window results in a better signalto noise ratio. The echoes may be removed in each window of time throughan adaptive filtering process. Further, the combined impulse responsescould be compared to echo characteristics of various sonic inputs. Forexample, the computing device may have a database of echocharacteristics for the various sonic inputs. These echo characteristicsmay have been determined during a calibration process of the microphonearray and/or stored in a database on the computing device. Thecomparison may result in determining a likelihood that a signal in thecombined impulse response is a sonic input. The likelihood determinationfacilitates isolating the sonic input from echoes in the audio signal toimprove the signal to noise ratio of the audio signal.

As another example, the signal to noise ratio can be improved usingbeamforming. In a polar domain, the audio signal may be present in arange of 0 to 360 degrees around the microphone array, albeit atdifferent magnitudes and phases depending on how the sonic input travelsfrom the audio source 710 to a microphone array. The microphone arraymay be arranged to capture the audio signals in an angular range of the360 degrees. For example, NMD 704 in the upper left corner of theenvironment 700 is shown at 712 to capture audio in a 100 degree angularrange. The audio signal received over a certain angular range, may bedivided into angular intervals 714. For example, in the polar domain,the audio signal may be received at over a 100 degree angular rangewhich is divided into five 20 degree angular intervals. Applyingbeamforming over a larger angular range and/or a smaller angularinterval may result in an improved signal to noise ratio.

The audio signal received in an angular interval may have certaincharacteristics. The characteristics of the audio signal may be comparedto known characteristics when a sonic input originates in thatdirection. These known characteristics may have been determined during acalibration process of the microphone array and/or stored in a databaseon the computing device. For example, an impulse response of the audiosignal may be compared to a known impulse response when sonic inputoriginated from a particular direction. This comparison may provide alikelihood that the sonic input of the audio signal originates in thatparticular direction. The direction of the sonic input may then be usedby the beamforming algorithm to improve the signal to noise ratio of theaudio signal.

If a playback device in the media playback system is playing audio atthe same time that the microphone array receives the audio signal, thenyet another algorithm (herein referred to as “subtraction of knownsignal method” and variants) may be used to improve the signal to noiseratio of the audio signal. The audio playing in the background is knownto the media playback system. It may be stored in an audio file orstreaming from a server. This known audio can be subtracted from thereceived audio signal to improve the signal to noise ratio of the audiosignal. For example, the audio playing in the background and the audiosignal may be represented as impulse responses of a certain duration.The impulse response of the audio playing in the background may besubtracted from the received audio signal so as to attenuate the audiothat is being played from the audio signal and improve the signal tonoise ratio of the audio signal.

The signal to noise ratio may be further improved based on one or moreof a microphone response of the microphone array, a playback deviceresponse, and a room response. The microphone array may have a responseindicative of its audio sensitivity versus frequency. The playbackdevice may have a response indicative its audio output versus frequency.The room response may be indicative of acoustic characteristics of theroom as described in U.S. patent application Ser. No. 14/481,511,entitled “Playback Device Calibration”, the contents of which is hereinincorporated by reference in its entirety. The microphone arrayresponse, the playback device response, and a room response may be usedto improve the signal to noise ratio. For example, an inverse of themicrophone array response, an inverse of the playback device response,and an inverse of the room response may be applied to the audio signalreceived by the microphone array prior to subtracting the impulseresponse of the audio being played back to improve the signal to noiseratio of the audio signal. The responses may also be used to improve thesignal measures determined by the other algorithms as well.

The methods described above are examples of various methods of improvingthe signal to noise ratio. One or several algorithms may be applied orcombined to improve the signal to noise ratio of the audio signal. Anarrangement among a playback device playing audio, a microphone array,and an audio source may determine the type of audio improvementalgorithm that is applied and the order in which it is applied. Forexample, if the playback device plays audio content and the audio sourceproduces sonic input in a same direction toward the microphone array,then the subtraction of the known audio method may be applied to improvethe signal to noise ratio. Beamforming may not be effective because theaudio source and playback device are facing in the same direction andthe beamforming would not be able to isolate the sonic input in view ofthe audio being played back by the playback device in the samedirection. Then, echo cancelation method may be applied to cancel outany echoes associated with reverberation in the environment. As anotherexample, the microphone array may be in between the playback device andthe audio source. If the audio source produces sonic input in adirection of the playback device and the playback device plays audio inthe direction of the audio source, then the beamforming may be appliedfirst if the microphone array is facing in the same direction as theaudio source. Then, an echo cancellation may be used to cancel echoes.Other arrangements are also possible in accordance with the disclosedembodiments and the arrangement of the media playback system in theenvironment.

The audio signal, as processed by one or more signal to noiseimprovement methods may be referred to herein as an improved audiosignal. In embodiments, the audio signal received by the microphonearray and the improved audio signal may be stored on the playbackdevice, controller device, or computing device as an audio file. Theaudio signal may be a digital file representing a spectral response ortemporal response. The spectral response may be an indication of how theaudio signal captured by the microphone array and the improved audiosignal varies with frequency. A power spectral density is an examplerepresentation of the spectral response. The temporal response may be anindication of how the audio signal and the improved audio signal changeswithin the room. The change may be characterized as a reverberation,delay, decay, or phase change of the audio signal. Additionally, oralternatively, the audio signal and improved audio signal may berepresented as a set of impulse responses or bi-quad filter coefficientsrepresentative of the audio signal, among others.

In the case of the audio signal being represented as impulse responses,the signal to noise ratio of the improved audio signal may be calculatedby dividing the impulse response of the improved audio signal with thereceived audio signal. As yet another example, the beamforming methodmay define a probability density function which indicates a likelihoodthat the sonic input the audio signal originates in a particulardirection. An integral of the probability density function may beindicative of a signal to noise ratio of the improved audio signal.Still alternatively, the signal to noise ratio may be based ondetermining for the probability density function those directions wherea first derivative of the likelihood is maximized, and integrating thoseregions to calculate the signal to noise ratio for the improved audiosignal. Other arrangements are also possible for calculating a signal tonoise ratio.

At least one signal to noise ratio or a plurality of signal to noiseratios may be associated with a microphone array. For example, the echocancellation algorithm provides an improved audio signal based on theaudio signal received by the microphone array. The signal to noise ratioof this improved audio signal may be calculated and associated with themicrophone array. As another example, beamforming may be performed in aplurality of directions to improve an an audio signal received in aparticular direction. The signal to noise ratio of this improved audiosignal with respect to direction may be calculated and associated withthe microphone array. For example, the audio signal may be processed atdirections of 20 degree angular intervals around the microphone array.Each 20 degree angular interval may have associated impulse response ofthe received audio signal, impulse response of the improved audiosignal, and signal to noise ratio.

FIGS. 8 and 9 present respective embodiments that can be implementedwithin the disclosed operating environment. Methods and the otherprocess disclosed herein may include one or more operations, functions,or actions. Although the blocks are illustrated in sequential order,these blocks may also be performed in parallel, and/or in a differentorder than those described herein. Also, the various blocks may becombined into fewer blocks, divided into additional blocks, and/orremoved based upon the desired implementation.

In addition, for the methods and other processes and methods disclosedherein, the flowchart shows functionality and operation of one possibleimplementation of present embodiments. In this regard, each block mayrepresent a module, a segment, or a portion of program code, whichincludes one or more instructions executable by a processor forimplementing specific logical functions or steps in the process. Theprogram code may be stored on any type of computer readable medium, forexample, such as a storage device including a disk or hard drive. Thecomputer readable medium may include non-transitory computer readablemedium, for example, such as computer-readable media that stores datafor short periods of time like register memory, processor cache andRandom Access Memory (RAM). The computer readable medium may alsoinclude non-transitory media, such as secondary or persistent long termstorage, like read only memory (ROM), optical or magnetic disks,compact-disc read only memory (CD-ROM), for example. The computerreadable media may also be any other volatile or non-volatile storagesystems. The computer readable medium may be considered a computerreadable storage medium, for example, or a tangible storage device. Inaddition, each block in the figures may represent circuitry that iswired to perform the specific logical functions in the process.

FIG. 8 is a flow chart 800 of functions associated with distributedprocessing to improving a signal measure, e.g., signal to noise ratio,of an audio signal received by a plurality of devices in a mediaplayback system. In one example, the disclosed functions may becoordinated and at least partially performed by a playback device, suchas one of the one or more playback devices in the media playback system.In another example, the disclosed functions may be coordinated and atleast partially performed by a computing device. In yet another example,the functions may be coordinated and at least partially performed by acontroller device. In another example, the disclosed functions may becoordinated and at least partially performed by a NMD. Otherarrangements are also possible.

Referring to FIG. 8, at 802, a set of signal measures corresponding toaudio signals processed based on first set of audio processingalgorithms may be received. At 804, a plurality of signal measures inthe set of signal measures may be identified. Then, at 806, the audiosignals corresponding to the identified plurality of signal measures maybe processed by one or more devices in the media playback system basedon a second set of audio processing algorithms. Additionally, the audiosignals may be processed based on spare computational power of a deviceof the one or more devices. At 808, the processed audio signals may becombined to produce a combined audio signal. The combined audio signalmay have an improved signal measure such as a signal to noise ratio ascompared to the audio signals processed at 802 and at 806. This improvedsignal measure allows for improved recovery of a sonic input of theaudio signal so that, for instance, in the case that the sonic input isa voice input, a server arranged with voice processing capabilities maybe able to interpret the voice input and perform a function associatedwith the voice input.

The functions of the example process shown in FIG. 8 will now bedescribed in more detail.

Starting at 802, a set of signal measures corresponding to audio signalsprocessed based on a first set of audio processing algorithms may bereceived. The playback device, controller device, and/or NMD of themedia playback system may each receive one or more audio signals. Afirst set of audio processing algorithms may be applied to an audiosignal received by a device to improve a signal to noise ratio of theaudio signal. The first set of audio algorithms may be the echocancellation method, beamforming method and/or subtraction of knownsignal method for a particular resolution. For example, the first set ofaudio processing algorithms may process impulse responses in a certainwindow size, e.g., 100 ms, or a certain angular interval of an angularrange, e.g., 20 degrees over a 100 degree range. In some embodiments,the window sand/or angular interval size that is processed may belimited by available processing power of the playback device, controllerdevice, NMD, or computing device that processes the audio signal. As aresult of the processing, one or more signal measures may be associatedwith each device. The signal measure may be a signal to noise ratio alsodetermined by the playback device, controller device, NMD, or computingdevice the processed audio signal. The one or more signal measures fromeach device in the media playback system may define a set of signalmeasures. For example, the set of signal measures may include the signalto noise ratio associated with a microphone array of a device or thesignal to noise ratio associated with receiving an audio signal in acertain direction.

At 804, a plurality of signal measures in the set of signal measures maybe identified. For example, the plurality of signal measures may bethose signal measures, e.g., signal to noise ratio, which are thehighest and/or those signal measures which are the lowest.

Then, at 806, the audio signals corresponding to the identifiedplurality of signal measures may be processed by one or more devices inthe media playback system so as to improve a signal measure of each ofthe audio signals. The audio signals may be processed based on a secondset of audio processing algorithms.

The audio signal may be processed based on the second set of audioprocessing algorithms to improve a signal to noise ratio. The second setof audio processing algorithms may be one or more of the echocancellation algorithm, beamforming algorithm, or known signalsubtraction algorithm, for instance, performed with a higher resolution.The higher resolution may be, for example, processing impulse responsesin a larger window size, e.g., 200 ms vs. 100 ms as compared to thefirst set of audio processing algorithms, a smaller angular interval,e.g., 5 degree intervals vs. 20 degree intervals as compared to thefirst set of audio processing algorithms, or a larger angular range,e.g., a 200 degree range vs. a 100 degree range as compared to the firstset of audio processing algorithms.

The devices in the media playback system have one or more processors.The one or more processors may have a maximum computational power. Themaximum computational power is the power available to perform functionsassociated with device. In the case of the controller device, themaximum computational power may be characterized as available clockcycles to process and playback the audio signal control the playbackdevices. In the case of the server, the maximum computational power maybe characterized as available clock cycles to source audio content tothe playback devices. In the case of the playback device, the maximumcomputational power may be characterized as available clock cycles toplay back audio content. The spare computational power may be thatcomputational power beyond what may be needed to perform functions ofthe device, such as to play back the audio in the case of a playbackdevice or control playback devices in the case of a controller device.

The higher resolution processing requires more computational power thanthe first set of audio processing algorithms. In this regard, the audiosignals may be processed in a distributed manner across one or moredevices in the media playback system based on the spare computationalpower available of a device to improve the signal to noise ratio beyondthat of the first set of audio processing algorithms. By using the sparecomputational power, performance of the media playback system does notdegrade with the additional processing associated with improving thesignal to noise ratio of the audio signal. The audio signals may bedistributed based on other criteria as well such as a speed of aprocessor of a device.

At 808, the processed audio signals may be combined into a combinedaudio signal. In some embodiments, the combined audio signal may beprovided to the server to recover the sonic input of the audio signal.

FIG. 9 is a flow chart 900 of functions that describes in more detailthe functions recited in FIG. 8 that may be performed in the distributedprocessing described in FIG. 8. In embodiments, these functions may beperformed by the computing device but could be performed by a playbackdevice, controller, and/or NMD.

At 902, the signal measures corresponding to the audio signals processedby devices in the media playback system may be received. For example,the playback device, NMD, and controller device may apply an audioprocessing algorithms to the audio signal or audio signals that arereceived by the device. The audio processing algorithm that is appliedmay be based on a first set of audio processing algorithms. In oneexample, the computing device may have a network interface andcommunication links that communicatively couple the computing device tothe playback device, NMD, and controller device to receive the signalmeasure or signal measures that is determined by each device. In anotherexample, the computing device instead of the device which receives theaudio signal may receive the audio signal from a device, apply the audioprocessing algorithms and/or determine a signal measure. Otherarrangements are also possible.

At 904, the signal measures may be stored in memory. The computingdevice may receive for each signal measure an indication of themicrophone array of the device associated with the signal measure, anindication of the device associated with the signal measure, and/or anindication of a direction associated with the signal measure. The signalmeasures stored in memory may be further associated with one or more ofthese indications.

FIG. 10 illustrates various examples of storing the signal measures inmemory. In embodiments, the signal measures may be stored in the form atable. If each device in the media playback system has one microphonearray, the signal measures may be stored in table 1002 which identifiesthe signal to noise ratio for each device/microphone array. The table1002 may be a two-dimensional matrix with each row having a signal tonoise ratio and each column identifying the device/microphone array. Ifa device in the media playback system has one or more microphone arrays,then the signal measures may be stored in a table 1004 which identifiesthe signal to noise ratio for each microphone array on each device. Thetable 1004 may be a two-dimensional matrix with each row identifying thesignal to noise ratios for each microphone array. If the signal to noiseratio is directional, e.g., determined by a beamforming algorithm, thenthe signal measure may be stored in a table 1006, e.g., two-dimensionalmatrix, which identifies the signal to ratio for a particular direction.The table could also have a third dimension which identifies theparticular device or microphone array associated with the signal tonoise ratio for a direction and/or microphone array, rather thanincluded in one of the two dimensions of the table. The table may takeother forms as well depending on the arrangement of the devices in themedia playback system and based on the processing algorithms used todetermine the signal to noise ratio.

The table may also be sorted such that the first entry in the table mayidentify the highest signal measure, e.g., signal to noise ratio, forthe audio signal received by a microphone array and the last entry mayidentify the lowest signal measure, e.g., signal to noise ratio, for theaudio signal received by a microphone array. In the case of the exampletables 1002-1006 of FIG. 10, SNR A may represent a highest signal tonoise measure and SNR F may represent a lowest signal to noise measure.The table, and for this matter how the signal measures are stored inmemory, may take other forms as well depending on the arrangement of thedevices in the media playback system and based on the processingalgorithms used to determine the signal measure. For example, the tablemay also be sorted based on the signal to noise ratios meeting athreshold level.

At 906, the computing device may determine the spare computational powerof the devices in the media playback system. Each device may indicateits spare computational power to a given device, such as a playbackdevice, controller device, or server. In one example, the media playbackmay define a state variable indicative of an amount of sparecomputational power associated with a device. This state variable may beperiodically updated and made available to the devices in the mediaplayback system. In some embodiments, the state variable may take theform of a flag which indicates that it has a spare computational power.

Various types of flags may be set depending on an amount of sparecomputational power available. The flag may take the form of one or morebits that are set on the device or some other device to indicate thatthe device has spare computational power. For instance, “000” mayindicate that the playback device has 50K clock cycles of computationalpower and “111” may indicate that the playback device has 1000K clockcycles of computational power. Based on the state variable, a givendevice, e.g., computing device, in the media playback system may obtainthe spare computational power for each device and generate a table thatidentifies for each device its spare processing power. For example, thegiven device may read the bits associated with the flag to determine thespare computational power associated with a particular device in themedia playback system.

At 908, an indication of the spare computational power of the devicesmay be stored in memory. The spare computational power may be furtherassociated with the indication of the device that has the sparecomputational power.

FIG. 10 illustrates an example of storing the computational power inmemory. The computational power may be stored in the form a table 1008.The table 1008 may identify a spare computational power and a device inthe media playback system having the spare computational power. Further,the table may be ordered such that a first entry in the table identifiesa device with a highest spare computational power in the media playbacksystem and a last entry in the table identifies a device with a lowestspare computational power in the media playback system. In this regard,table 1008 indicates that device 5 has the highest spare computationalpower of 8 units and device 1 has the lowest spare computational powerof 2 units. The units may represent a certain amount of available clockcycles for a processor. The table may store indications other than sparecomputational power as well so long as spare computational power may bedetermined from the stored indication.

At 910, processing tasks are assigned to the devices identified in thetable determined at 908 so as to improve the signal to noise ratio ofthe processed audio signals. The processing tasks may be associated witha second set of audio processing algorithms, and may include one or moreof a higher resolution echo cancellation, beamforming method, and/orsubtraction of known signal method. The echo cancellation method and thesubtraction of known signal methods may be higher resolution because alonger impulse response of the audio signal is processed as compared thesignal measures processed with the first set of signal improvementalgorithms. The processing over a longer impulse results in an improvedidentification and cancellation of echoes and noise. The beamforming maybe higher resolution because the audio signal is processed in smallerangular intervals and/or over a greater number of directions. Forexample, the audio signal is processed at 5 degree intervals rather than20 degree intervals for a 200 degree angular range rather than a 100degree angular range. Other arrangements are also possible.

The processing tasks may be assigned to devices based on available spareprocessing power available in the media playback system. The echocancellation and beamforming may require a certain computational powerto be performed. Further, the computational power for performing echocancellation may be less than that for performing beamforming to improvea signal to noise ratio. Accordingly, processing tasks may be assignedbased on what spare computational power is available on a device (e.g.,a threshold level) and the computational power needed for a processingtask. For example, using table 1008, the processing tasks requiring themost computational power may be assigned to the device with highestavailable spare processing power, and then the processing task requiringthe next most computational power may be assigned to the device with thenext highest available spare processing power etc. As another example,processing tasks associated with only the echo cancellation algorithmmay be assigned to all of the devices in the media playback system ifthe spare computational power across all device is low but enough tosupport echo cancellation. As yet another example, processing tasksassociated with both the beamforming algorithm and echo cancellation maybe assigned if the spare computational power across all device high andenough to support both algorithms. In yet another example, some devicesmay be assigned a processing task of echo cancellation and other devicesmay be assigned a processing task of beamforming depending on eachindividual spare processing power. Other arrangements are also possible.

In some embodiments, a total spare processing power available (e.g., sumof spare processing power for each device) may be less than what isneeded to process all of the audio signals that are received by thedevices in the media playback system with desired processing algorithms.In this situation, the processing tasks may be assigned based on goalsas a result of the audio signal processing. For example, a decision maybe made that a high signal to noise ratio is desired for the audiosignals that are received from some of the devices. If a high signal tonoise ratio is desired, then processing tasks such as both thebeamforming algorithm and echo cancellation may be assigned to the oneor more devices. On the other hand, a decision may be made that a lowersignal to noise ratio is acceptable so that audio signals that arereceived from all or many of the devices are processed. If the lowersignal to noise ratio is acceptable, then processing tasks that use lowcomputational power such as only echo cancellation may be assigned tothe one or more devices.

The processing tasks may be assigned until the spare computationalresources is exhausted, or some threshold level of spare computationalresources remain for a device or across all devices. Alternatively, theprocessing tasks may be assigned across the devices so that the sparecomputational power is reduced across all devices in proportion. Otherarrangements are also possible.

At 912, certain of the audio signals identified by corresponding signalmeasures may be processed. The processing may be based on the processingtasks assigned to the devices to result in improved audio signals. Forexample, the audio signal for the device, microphone array, or directionof the microphone array that has the highest signal to noise ratio asdefined by the table of signal to noise ratios may be assigned to thedevice with the highest spare processing power for processing. Then, theaudio signal associated with the next highest signal to noise ratio maybe assigned to the device with the next highest signal to noise ratiofor processing until all desired audio signals are assigned to thedevices associated with processing tasks. By assigning processing tasksin this manner, the overall performance of the media playback devicedoes not degrade because the processing is performed based on spareprocessing power and not processing power which would otherwise be usedto play back audio.

Other arrangements are also possible for assigning the audio signals tobe processed. For instance, a user may specify that certain audiosignals may be processed based on knowledge of a relationship betweenthe audio source and microphone array. For instance, if it is known thatthe sonic input is received directly the microphone array, then theaudio signal should be processed regardless of the actual signal tonoise ratio of the audio signal. Similarly, if it is known, that if thesonic input is received indirectly by the microphone array, then theaudio signal should not be processed further regardless of the signal tonoise ratio of the audio signal.

The audio signals processed by each device result in an improved audiosignal with a higher signal to noise ratio than what was determined bythe first set of audio processing algorithms. The improved audio signalmay also be weighted based on a confidence or likelihood that theimproved audio signal accurately represents the sonic input. Forexample, the improved audio associated with a certain direction may beweighed more heavily than the improved audio associated with anotherdirection if the likelihood is higher that the sonic input is comingfrom the certain directions. As another example, the improved audiosignal of one device may be weighted heavier than the improved audiosignals of another device if one device is closer to the sonic inputthan the other device. Other arrangements are also possible.

At 914, the improved audio signals (with or without weighing) may becombined to form a combined audio signal. By combining the improvedaudio signals, noise is cancelled resulting in a combined audio signalwith a higher signal to noise ratio than any of the improved audiosignals making up the combined audio signal. At 916, this combined audiosignal may be then passed to a computing device such as a server. In theevent that the audio signal has a voice input, the computing device mayattempt to interpret the voice input to determine a function associatedwith the voice input.

Methods and the other process disclosed herein may include one or moreoperations, functions, or actions. Although the blocks are illustratedin sequential order, these blocks may also be performed in parallel,and/or in a different order than those described herein. Also, thevarious blocks may be combined into fewer blocks, divided intoadditional blocks, and/or removed based upon the desired implementation.

In addition, for the methods and other processes and methods disclosedherein, the flowchart shows functionality and operation of one possibleimplementation of present embodiments. In this regard, each block mayrepresent a module, a segment, or a portion of program code, whichincludes one or more instructions executable by a processor forimplementing specific logical functions or steps in the process. Theprogram code may be stored on any type of computer readable medium, forexample, such as a storage device including a disk or hard drive. Thecomputer readable medium may include non-transitory computer readablemedium, for example, such as computer-readable media that stores datafor short periods of time like register memory, processor cache andRandom Access Memory (RAM). The computer readable medium may alsoinclude non-transitory media, such as secondary or persistent long termstorage, like read only memory (ROM), optical or magnetic disks,compact-disc read only memory (CD-ROM), for example. The computerreadable media may also be any other volatile or non-volatile storagesystems. The computer readable medium may be considered a computerreadable storage medium, for example, or a tangible storage device. Inaddition, each block in the figures may represent circuitry that iswired to perform the specific logical functions in the process.

IV. Conclusion

The description above discloses, among other things, various examplesystems, methods, apparatus, and articles of manufacture including,among other components, firmware and/or software executed on hardware.It is understood that such examples are merely illustrative and shouldnot be considered as limiting. For example, it is contemplated that anyor all of the firmware, hardware, and/or software aspects or componentscan be embodied exclusively in hardware, exclusively in software,exclusively in firmware, or in any combination of hardware, software,and/or firmware. Accordingly, the examples provided are not the onlyway(s) to implement such systems, methods, apparatus, and/or articles ofmanufacture.

Additionally, references herein to “embodiment” means that a particularfeature, structure, or characteristic described in connection with theembodiment can be included in at least one example embodiment of aninvention. The appearances of this phrase in various places in thespecification are not necessarily all referring to the same embodiment,nor are separate or alternative embodiments mutually exclusive of otherembodiments. As such, the embodiments described herein, explicitly andimplicitly understood by one skilled in the art, can be combined withother embodiments.

The specification is presented largely in terms of illustrativeenvironments, systems, procedures, steps, logic blocks, processing, andother symbolic representations that directly or indirectly resemble theoperations of data processing devices coupled to networks. These processdescriptions and representations are typically used by those skilled inthe art to most effectively convey the substance of their work to othersskilled in the art. Numerous specific details are set forth to provide athorough understanding of the present disclosure. However, it isunderstood to those skilled in the art that certain embodiments of thepresent disclosure can be practiced without certain, specific details.In other instances, well known methods, procedures, components, andcircuitry have not been described in detail to avoid unnecessarilyobscuring aspects of the embodiments. Accordingly, the scope of thepresent disclosure is defined by the appended claims rather than theforgoing description of embodiments.

When any of the appended claims are read to cover a purely softwareand/or firmware implementation, at least one of the elements in at leastone example is hereby expressly defined to include a tangible,non-transitory medium such as a memory, DVD, CD, Blu-ray, and so on,storing the software and/or firmware.

I claim:
 1. A first playback device comprising: at least one processor;a network interface; one or more microphones; at least onenon-transitory computer-readable medium; and program instructions storedon the at least one non-transitory computer-readable medium that areexecutable by the at least one processor such that the first playbackdevice is configured to: receive, via the one or more microphones, a setof voice signals; process the set of voice signals using a first set ofaudio processing algorithms to determine a set of signal measurescorresponding to the set of voice signals; identify, from the set ofvoice signals, at least two voice signals that are to be furtherprocessed so as to improve respective signal measures of the at leasttwo voice signals; determine that the first playback device does nothave a threshold amount of computational power available to furtherprocess the at least two voice signals; receive an indication of anavailable amount of computational power of a second playback device;based on the received indication of the available amount of computationpower of the second playback device, send the at least two voice signalsto the second playback device; cause the second playback device toprocess the at least two voice signals using a second set of audioprocessing algorithms; receive, from the second playback device, theprocessed at least two voice signals; and combine the processed at leasttwo voice signals into a combined voice signal.
 2. The first playbackdevice of claim 1, wherein the program instructions that are executableby the at least one processor such that the first playback device isconfigured to receive the indication of the available amount ofcomputational power of the second playback device comprises programinstructions that are executable by the at least one processor such thatthe first playback device is configured to receive the indication of theavailable amount of computational power of the second playback devicefrom a network device.
 3. The first playback device of claim 1, whereinthe program instructions that are executable by the at least oneprocessor such that the first playback device is configured to receivethe indication of the available amount of computational power of thesecond playback device comprises program instructions that areexecutable by the at least one processor such that the first playbackdevice is configured to receive the indication of the available amountof computational power of the second playback device from the secondplayback device.
 4. The first playback device of claim 1, wherein atleast a portion of the set of voice signals received by the one or moremicrophones of the first playback device is additionally received by oneor more microphones of the second playback device.
 5. The first playbackdevice of claim 1, wherein the at least one non-transitorycomputer-readable medium further comprises program instructions that areexecutable by the at least one processor such that the first playbackdevice is configured to: receive an indication of an available amount ofcomputational power of a third playback device; compare the availableamount of computational power of the second playback device with theavailable amount of computational power of the third playback device;and based on comparing the available amount of computational power ofthe second playback device with the available amount of computationalpower of the third playback device, send the at least two voice signalsto the second playback device for processing.
 6. The first playbackdevice of claim 1, wherein each of the first set of audio processingalgorithms and the second set of audio processing algorithms comprisesat least one of an echo cancellation algorithm or a beamformingalgorithm.
 7. The first playback device of claim 1, wherein a resolutionof the first set of audio processing algorithms is lower than aresolution of the second set of audio processing algorithms.
 8. Thefirst playback device of claim 1, wherein the at least onenon-transitory computer-readable medium further comprises programinstructions that are executable by the at least one processor such thatthe first playback device is configured to: send the combined voicesignal to a network device.
 9. The first playback device of claim 1,wherein a signal measure of the combined voice signal is higher than arespective signal measure of any of the set of voice signals and any ofthe processed at least two voice signals.
 10. A non-transitorycomputer-readable medium comprising program instructions stored thereonthat are executable by at least one processor such that a first playbackdevice is configured to: receive, via one or more microphones of thefirst playback device, a set of voice signals; process the set of voicesignals using a first set of audio processing algorithms to determine aset of signal measures corresponding to the set of voice signals;identify, from the set of voice signals, at least two voice signals thatare to be further processed so as to improve respective signal measuresof the at least two voice signals; determine that the first playbackdevice does not have a threshold amount of computational power availableto further process the at least two voice signals; receive an indicationof an available amount of computational power of a second playbackdevice; based on the received indication of the available amount ofcomputation power of the second playback device, send the at least twovoice signals to the second playback device; cause the second playbackdevice to process the at least two voice signals using a second set ofaudio processing algorithms; receive, from the second playback device,the processed at least two voice signals; and combine the processed atleast two voice signals into a combined voice signal.
 11. Thecomputer-readable medium of claim 10, wherein the program instructionsthat are executable by the at least one processor such that the firstplayback device is configured to receive the indication of the availableamount of computational power of the second playback device comprisesprogram instructions that are executable by the at least one processorsuch that the first playback device is configured to receive theindication of the available amount of computational power of the secondplayback device from a network device.
 12. The computer-readable mediumof claim 10, wherein the program instructions that are executable by theat least one processor such that the first playback device is configuredto receive the indication of the available amount of computational powerof the second playback device comprises program instructions that areexecutable by the at least one processor such that the first playbackdevice is configured to receive the indication of the available amountof computational power of the second playback device from the secondplayback device.
 13. The computer-readable medium of claim 10, whereinat least a portion of the set of voice signals received by the one ormore microphones of the first playback device is additionally receivedby one or more microphones of the second playback device.
 14. Thecomputer-readable medium of claim 10, further comprising programinstructions stored thereon that are executable by the at least oneprocessor such that the first playback device is configured to: receivean indication of an available amount of computational power of a thirdplayback device; compare the available amount of computational power ofthe second playback device with the available amount of computationalpower of the third playback device; and based on comparing the availableamount of computational power of the second playback device with theavailable amount of computational power of the third playback device,send the at least two voice signals to the second playback device forprocessing.
 15. The computer-readable medium of claim 10, wherein eachof the first set of audio processing algorithms and the second set ofaudio processing algorithms comprises at least one of an echocancellation algorithm or a beamforming algorithm.
 16. Thecomputer-readable medium of claim 10, wherein a resolution of the firstset of audio processing algorithms is lower than a resolution of thesecond set of audio processing algorithms.
 17. The computer-readablemedium of claim 10, further comprising program instructions storedthereon that are executable by the at least one processor such that thefirst playback device is configured to: send the combined voice signalto a network device.
 18. The computer-readable medium of claim 10,wherein a signal measure of the combined voice signal is higher than arespective signal measure of any of the set of voice signals and any ofthe processed at least two voice signals.
 19. A method comprising:receiving, by a first playback device via one or more microphones of thefirst playback device, a set of voice signals; processing, by the firstplayback device, the set of voice signals using a first set of audioprocessing algorithms to determine a set of signal measurescorresponding to the set of voice signals; identifying, by the firstplayback device and from the set of voice signals, at least two voicesignals that are to be further processed so as to improve respectivesignal measures of the at least two voice signals; determining, by thefirst playback device, that the first playback device does not have athreshold amount of computational power available to further process theat least two voice signals; receiving, by the first playback device, anindication of an available amount of computational power of a secondplayback device; based on the received indication of the availableamount of computation power of the second playback device, sending, bythe first playback device, the at least two voice signals to the secondplayback device; causing, by the first playback device, the secondplayback device to process the at least two voice signals using a secondset of audio processing algorithms; receiving, by the first playbackdevice and from the second playback device, the processed at least twovoice signals; and combining, by the first playback device, theprocessed at least two voice signals into a combined voice signal. 20.The method of claim 19, further comprising: receiving, by the firstplayback device, an indication of an available amount of computationalpower of a third playback device; comparing, by the first playbackdevice, the available amount of computational power of the secondplayback device with the available amount of computational power of thethird playback device; and based on comparing the available amount ofcomputational power of the second playback device with the availableamount of computational power of the third playback device, sending, bythe first playback device, the at least two voice signals to the secondplayback device for processing.